1. Field of the Invention
The present invention relates to a back lighting plate.
2. Description of Prior Art
As shown on FIG. 3, a conventional variable-wavelength back lighting plate in that the light emitting diodes 83 are coated on phosphide compounded fluorescent material 84 on the outside surface directly so as to change the wavelength, in order to give out the desired colour can be saw by human eyes. But during a long-term working in a high temperature the phosphide may be failed so that the wavelength restores to the original state.
For innovating on above-mentioned product, the products in the market so far, as shown on FIG. 4, are designed into a new structure, in which a diffusion film coated with the fluorescent material 84 is covered on the top is surface of the back lighting plate instead of coating the phosphide on directly, so that when the light passing through the fluorescent material from front side, the wavelength (the colour of the light) is changed, thereby the diminution problem of the fluorescent material is solved, but in the manufacturing, the rate of producing pin-hole is increased so that the production cost is not decreased to a proper level.
For spreading the luminosity on surface of the back lighting plate 8 in uniform distribution (referring to FIG. 3 and FIG. 4), the top surface of the back lighting plate 8 is covered a diffusion film 81, so that the light source is reflected by the reflection paper 82 laid on the bottom side, then is diffused to the outside uniformly by the diffusion film 81. But in manufacturing, this procedure takes much time so that the production cost goes up virtually. So the cost of the conventional product includes the costs of a back plate, a reflection paper and a diffusion film attached with fluorescent material, and the cost of processes.
It is therefore a main object of the present invention to provide a back lighting plate, in which the procedure of gluing the diffusion film and the cost are saved meanwhile guarantee the light intensity and the colour spread on the surface uniformly.
A back lighting plate, which contains many reflecting fine grains at inside uniformly and a fluorescent reflection coating at the bottom, achieves this object.
Above-mentioned back lighting plate has an atomised top surface.
In accordance with this structure, the back lighting plate containing the reflecting grains replaces the conventional diffusion film to supply a good reflecting diffusion environment and make the light be reflected and absorbed fully by the fluorescent reflecting coating so as to meet the expected colour and evenness degree. Meanwhile the atomised top surface inflects the light again as passing through to improve the uniform light effect.